I have one pair of heavy duty wick-out-the-water thick warm somethings. WOre them under sweatpants today, stopped to feed my friends' cat and *almost* went back for the car when the weather channel informed me that things had turend to freezing rain (and the metal guard rail down the steps confirmed it). The roads were still warm, though.
My feet got a bit damp and cold (sneakers over socks... they're soaked and leaning against the computer to be dry by the time I leave... as soon as office mate is gone I'll lean dangle the sweats but I don't want to totally gross him out - you can't see 'em once they're dangling behind my desk but it's the process...
Other than that, though, it was fun! I was thinking maybe it *wasn't* really freezing rain until I arrived and looked down at my jacket and it was all crunchy and covered with ice, and my handlebars, too... I figured that I was going to give a 15-mile present to the planet with a half-gallon less of fossil fuel consumption ... but it was a present to me, too. (Okay, and I stepped on the scale... I need to get back under 150... )

And don't be afraid of below freezing! It's not that different. If you went from 50 to 35, you can also go from 35 to 20. Layers, Layers, Layers :-)